Every year since the 1990s, Apple has held a Worldwide Developers Conference, a five-day-long event that invites developers to learn about Apple software from the experts. This year is no exception, and with a two-hour-long keynote set to kick off the event on 2 June, you can expect new software and hardware including iOS 8, OS X 10.10, new MacBooks, and maybe even an iWatch and an iPhone 6. Read on to find out the latest rumours about what Apple is planning to launch at WWDC 2014, and how plausible those rumours are.

When is WWDC 2014?

WWDC 2014 will run from 2 June to 6 June at San Francisco's Moscone West venue. It will start with a keynote at 10am on 2 June (that's 6pm to those of us in the UK), and we'll be covering the keynote live here at PC Advisor. Expect to see Apple CEO Tim Cook on stage, joined by fellow Apple executives, who'll be unveiling what's been going on behind the scenes at Apple.

"At this year's five-day conference, developers from around the world will learn about the future of iOS and OS X, giving them the latest tools and technologies to continue creating the most innovative apps for the millions of iOS and Mac customers worldwide," said Apple in a press release announcing WWDC 2014.

"We look forward to sharing with [developers] our latest advances in iOS and OS X so they can create the next generation of great apps," Apple's SVP of worldwide marketing, Phil Schiller, has said. That means the successor to iOS 7 (presumably iOS 8) and the successor to OS X 10.9 Mavericks (currently dubbed OS X 10.10) are pretty much guaranteed to be shown off during the keynote.

Intriguingly, Samsung has announced that it is hosting a health-focused event just days before Apple's WWDC 2014 keynote, on 28 May.

What to expect at WWDC 2014

Looking back at Apple's WWDC history, it's clear that we'll get new software from Apple as well as new hardware at this year's event. Apple used WWDC 2013 to unveil OS X 10.9 Mavericks, iOS 7, a new Mac Pro, a new MacBook Air, iTunes Radio and iWork for iCloud.

So what can we expect from Apple at WWDC 2014? Read on to find out.

WWDC keynote rumours: OS X 10.10

As mentioned above, the next version of Mac OS X, commonly referred to as OS X 10.10, is extremely likely to be previewed at WWDC 2014. Apple usually uses WWDC to show off new versions of software, which it then immediately releases as beta versions before releasing the software to the public in the following months. Rumour has it Apple design chief Jony Ive has got his hands on OS X 10.10, so it could take some inspiration from iOS 7.

According to reports from 9To5Mac, Apple is planning to use its WWDC 2014 keynote to focus on OS 10.10, though we hardly think it'll talk about it for the whole two hours.

Which of these new OS X 10.10 features will be previewed at the WWDC Keynote?

WWDC keynote rumours: iOS 8

That's why we think iOS 8 is going to get some decent airtime, too. Apple gave iOS a huge redesign with iOS 7, so we're not expecting anything quite so drastic this year, but expect to see some tweaks and improvements that are bound to be welcome. There's talk of a new 'Healthbook' app (remember we said Samsung is hosting a health-related event just days before?) which could well be related to the iWatch - Apple's rumoured smartwatch device. See: iOS 8 rumours

WWDC keynote rumours: Retina MacBook Air

We're expecting at least one piece of hardware to come out of WWDC 2014, and right now it's pretty much anyone's guess. However, based on Apple's launch history and the speculation that's flying around the web, one of the most likely candidates is a Retina MacBook Air.

Apple recently released an update to the MacBook Air, but that update didn't bring Retina to the lightweight notebook competitor. It's widely rumoured that Apple is planning on bringing a high-resolution display to the MacBook Air, so it's quite possible that a Retina model is in store for us next month. See: MacBook Pro vs MacBook Air comparison

WWDC keynote rumours: new Retina MacBook Pro

Apple's other MacBook line-up - the MacBook Pro range - could get an update too. Apple last launched new models in October, so it's not been too long since we got new MacBook Pros from Apple, but it's certainly possible that Apple will decide to update them with better specs next month. It could also be the last we see of the non-Retina MacBook Pro, which is rumoured to be about to get the chop from the Apple family.

WWDC keynote rumours: new Mac mini

The Mac mini seems to have been a bit neglected over the past few years. The Mac mini hasn't been updated since October 2012, and that's led to talk about plans to discontinue to tiny desktop computer. Perhaps WWDC 2014 will see an update to the Mac mini at last, though rumours about such announcement have been scarce.

WWDC keynote rumours: iWatch

With the rumours of the iOS 8 Healthbook app comes speculation that Apple will show off an iWatch alongside it. We know that Apple is working on new product categories, and a wearable device seems quite likely to be the mysterious device it's talking about, but we're not certain Apple will show it off in June.

The first reason for our doubt about the iWatch is the iPhone - we think the iWatch will work closely with the iPhone 6, so Apple will probably host a separate event in September or October to unveil both of those products (though there are actually some people predicting the iPhone 6's arrival in June - more on that in a minute).

The second reason is that, while we've heard SO much about the iWatch, we've never actually seen any evidence that it exists. Apple may be notorious for its secrecy, but with the amount of iPhone and iPad leaks we've seen over the past few years, we think it's highly unlikely that Apple has managed to keep the iWatch completely under wraps this whole time. See: iWatch rumours

WWDC keynote rumours: iPhone 6

Yep, it's true. There are some rumours that the iPhone 6, which is expected to be bigger and better than the iPhone 5S, will be unveiled at WWDC 2014. Now this seems highly unlikely to us, but we can't rule it out completely. After all, we've got photos of leaked mockups and dummy models of the iPhone 6 coming out of our ears already, so development of the new smartphone seems to be well underway. See: iPhone 6 rumours

WWDC keynote rumours: Apple TV

We've been eagerly awaiting a new Apple TV. It's been two years since the last proper update of the set-top box, and since then, we've seen rival products from Google, Amazon and loads more enter the market. But we haven't given up hope, and we're keeping our fingers crossed that WWDC 2014 will see a new, all-singing, all-dancing Apple TV, though we're not convinced our wishes will come true.

WWDC keynote rumours: new iPads

We haven't forgotten about Apple's iPads, don't worry! But we've left them until last because we think they're the least likely to get an update at WWDC 2014. The iPad Air was introduced in October, alongside a new Retina iPad mini, so we're expecting an October 2014 launch for the next generation of both devices.

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